This invention relates to dextranase-containing oral compositions such as dentifrices, mouthwashes or the like, and more particularly, to such oral compositions capable of keeping dextranase effective and stable for a long period of time and providing a pleasant sensation during use.
It is well known in the art to incorporate dextranase in oral compositions such as dentifrices as an active ingredient for caries prophylaxis to prevent the formation of dental plaque. For examples, U.S. Pat. Nos. 3,574,824, 3,622,661, 3,686,393, 3,751,561, 3,981,989, 3,991,177, 4,115,546, 4,140,758 and 4,150,113, British Patent Nos. 1,373,003 and 1,427,300, and German Patent No. 1,948,469 disclose dextranase-containing oral compositions.
Inconveniently, dextranase tends to be deactivated by moisture, anionic surfactants and other ingredients in oral compositions. A number of approaches were proposed to keep dextranase stable in oral compositions, but none of them could successfully stabilize dextranase particularly when the oral compositions were stored at elevated temperatures. There is a need for a method capable of keeping dextranase more stable in oral compositions.
Oral compositions such as dentifrices, because of their intended use in the mouth, should preferably taste good and provide high foaming properties to ensure a pleasant mouth feel. Furthermore, for dentifrices, particularly toothpastes, it is desired that a creamy or gel mass be smoothly extrudable from a collapsible tube. Most masses tend to deteriorate in extrudability when aged for a long time at low temperatures. Smooth extrusion from a tube at low temperatures is thus one of the important requirements for dentifrices.